Why Is My Coffee Grinder Not Grinding? How to Clean Espresso, Pour-Over, and Single-Origin Coffee Grinders

Many friends who originally used manual grinders have purchased electric grinders to grind coffee beans, aiming to free their hands from the tedious grinding process. However, electric grinders differ from manual ones and require attention to many details during use. A single mistake can easily shorten the grinder's lifespan and significantly reduce grinding quality.

Recently, many friends have asked FrontStreet Coffee various questions about grinders at our store, so today FrontStreet Coffee will share some details worth noting when using electric grinders!

1. Pay Attention to "Purging" and "Cleaning"

Yes, FrontStreet Coffee is mentioning two types of cleaning here. Although both involve cleaning the grinder, their specific methods and functions are completely different. The first purging is performed when we use the grinder to grind beans! If you often visit coffee shops for pour-over coffee, you might have noticed that baristas typically pre-grind a few coffee beans before grinding the beans for brewing.

The purpose of this action is not to test the grind size but to perform a quick "cleaning" of the grinder's burrs. As we all know, no matter how high-quality the grinder is, it will experience "retention" - meaning the ground coffee powder will be slightly less than the beans put in. This is because some coffee powder gets trapped in the burrs or internal gaps during grinding and cannot exit. Additionally, some darker roasted or more flavorful coffee beans will leave their oils and aromas attached to the burrs.

Without cleaning, these aromas, oils, and coffee powder "impurities" will mix into the next batch of ground coffee beans, directly affecting the coffee's flavor and cleanliness. Therefore, we need to use a small amount of coffee beans before actual grinding to remove these substances and avoid impacting coffee quality. Generally, FrontStreet Coffee uses 1-2g or 3-4 coffee beans for purging. Too little won't be effective, while too much would be wasteful. However, when we grind dark roasted coffee beans frequently, we need to perform regular deep cleaning of the grinder - this is the second "cleaning" that FrontStreet Coffee mentioned.

Because dark roasted coffee beans often carry more oils, and these oils cannot be completely removed simply by using coffee beans. When oils remain in the burrs for too long, they can produce off-flavors due to oxidation and other phenomena. Moreover, oils will increase the grinder's retention, causing more powder to remain inside. Therefore, if you grind dark roasted beans frequently, you should clean your grinder more frequently as well. As for how to clean it, FrontStreet Coffee has shared methods in previous articles that you can search for and learn about. (However, since different grinder constructions are not universal, it's best to request relevant cleaning tutorials from the manufacturer.)

2. Start First, Add Beans Later

This is also an operation that FrontStreet Coffee often shares! When grinding coffee beans, it's best to start the grinder first and then add the beans for grinding. This approach offers two benefits: first, it reduces burr wear and the probability of jamming! When the grinder starts, the burrs go from stationary to stable rotation during a brief transition period, which typically ranges from 0.5 to 1 second depending on the grinder's quality.

If we choose to add beans first and then start the grinder, the presence of coffee beans will increase the resistance when the burrs start, adding load to the motor. For some small household grinders, if the density of the beans being ground is high, this can easily cause jamming or failure due to motor overload. Additionally, this will increase burr wear and shorten their lifespan. Although the wear might be minimal, it accumulates over time. Therefore, FrontStreet Coffee recommends starting the grinder first when grinding coffee beans, and then adding the coffee beans once the burrs are rotating stably. This not only effectively extends the life of the grinder and burrs but also improves the quality of the coffee powder due to consistent rotation speed.

3. Regularly Check the Grind Size

FrontStreet Coffee often recommends purchasing a #20 sieve to measure the sieve rate of coffee powder. This is not only to help everyone use the same parameters/grind size for brewing coffee but also because it can be used to calibrate the grinder's grind settings.

Have you noticed that as the grinder's usage time increases, the particles it produces become coarser? Or perhaps the brewed coffee becomes increasingly weaker, starting to show signs of under-extraction? This is the result of burr wear. Each time we grind coffee beans, we cause slight wear to the burrs. When wear accumulates, the burr spacing becomes wider, and the coffee powder ground at the same setting becomes coarser.

When the grind becomes coarser, the coffee brewed with the same parameters will naturally have less extracted material, so both the flavor and texture of the coffee will be less rich and full-bodied compared to the beginning. Therefore, if you want to brew coffee with rich flavor and full-bodied texture again, you need to adjust the grind to be finer until it matches the original degree. Through a #20 sieve, we can directly find the corresponding grind setting. It's worth mentioning that this situation is most noticeable in espresso grinders - just looking at the scale indicator, you'll see that the value has become much smaller than before.

4. Watch for Fine Powder Blockage

"Spinning without grinding" - this is a situation commonly found in espresso grinders. Simply put, when we start the grinder, the burrs are rotating but not grinding any coffee beans.

This situation is most likely caused by grinding too finely, resulting in coffee powder blocking the burrs. If you encounter this situation, the first step is to observe whether it's caused by fine powder blockage. If so, you can choose one of the following two solutions: The first is to directly adjust the grind coarser, increasing the spacing to allow grinding to resume; the second is to clean the grinder as mentioned earlier by FrontStreet Coffee. Once the fine powder blocking the burrs is cleared, the grinder can resume its grinding work. (Don't follow this example)

The above are some small details to pay attention to when using electric grinders. If you have additional tips, feel free to leave a comment~

Important Notice :

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